API MPMS 6.2:2004 pdf download

API MPMS 6.2:2004 pdf download.Manual of Petroleum Measurement Standards Chapter 6- .Metering Assemblies Section 2- Loading Rack Metering Systems.
4.5.3 Check Valves
Check valves are reqLlired to prevent hackflow. siphoning with low tank head. and cross Contamination of product during blending applications. When choosing the proper check valve, consider pressure drop and slamming of the flapper. which can cause damage when the valve opens and closes.
4.5.4 Flow Control Valves
Flow control valves must be installed downstream of the meter. These valves should provide a smooth opening and closing and be capable of stable (low control. Additionally. quick operation is required to prevent overfill.
The manufacturer’s recommended flow control range should not be exceeded. This could result in poor flow control. unsafe shutofl. inaccurate measurement, and premature wear.
The flow control valve is typically controlled by an eketronic preset to reduce the discharge rate at stan-up or before shutdown, to control the delivery rate and to shut off the flow at the conclusion of the delivery. Because most flow control valves depend on difTcrential pressure for proper operation. care should be taken to ensure that operating pressures provide for adequate specd of operation.
5.1 DISPLACEMENT METERS
L)isplacement meters API MPMS Cli. 5.2) will require some form of signal output. either mechanical or electronic. Note that whenever a meter with a manual calibrator mounted below the pulser is retrofitted with an electronic pulse output device, the calibrator must be removed.
Displacement meters typically can be mounted either venically or horizontally. Consult the manufacturer for proper orientation or issues of bearing load and wear. [)isplacemenl mtrs do not require flow conditioning. See Figure 3 for a typical installation.
5.2 TURBINE METERS
The performance of turbine meters (API MPMS Ch 5.3) is aulected by liquid swirl and non-uniform velocity tlaminar) profiles that arc induced by upstream and downstream piping conhgurahons, valves, pumps, joint misalignment, protruding gaskets, welding projections, additive injection points, thermowell or other obstructions. Flow conditioning shall be used to overcome swirl and non-uniftmi velocity profiles. Upstream flow conditioning requires the use of a how conditioning plate, suflicient length of pipe, or a combination of straight pipe and straightening elements. Flow conditioning is required downstream of the meter, generally, five pipe diameters is recommended.
A flow conditioning plate is a perforated plate or wafer that has a unique geometric pattern of holes or openings to provide flow conditioning with a minimum use of space. Flow conditioning plates provide a uniform flow distribution with low turbulence intensity and are designed to eliminate swirl and produce a fully developed velocity flow profile. They function by greatly reducing the scale of turbulence into a large number of small disturbances, which coalesce and rapidly diminish.
The position. size and number of holes in the plate are designed to provide a uniform velocity profile. Any misalignment of the plate could cause errors in registration. Manufacturers otlen design plates as an integral part of the turbine meter design to ensure alignment. Due to possible niisalignmcnt. caution is recommended for plates that bolt between flanges and are not integral to the turbine meter. Periodic inspection of the plate is necessary to prevent fouling, plugging or distortion. Any disturbance of the plate requires that the meter be re-proved.